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      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 ******************************************************************************
      5 * Copyright (C) 2015, International Business Machines
      6 * Corporation and others.  All Rights Reserved.
      7 ******************************************************************************
      8 * sharedobject.cpp
      9 */
     10 #include "sharedobject.h"
     11 #include "uassert.h"
     12 
     13 U_NAMESPACE_BEGIN
     14 
     15 SharedObject::~SharedObject() {}
     16 
     17 UnifiedCacheBase::~UnifiedCacheBase() {}
     18 
     19 void
     20 SharedObject::addRef(UBool fromWithinCache) const {
     21     umtx_atomic_inc(&totalRefCount);
     22 
     23     // Although items in use may not be correct immediately, it
     24     // will be correct eventually.
     25     if (umtx_atomic_inc(&hardRefCount) == 1 && cachePtr != NULL) {
     26         // If this object is cached, and the hardRefCount goes from 0 to 1,
     27         // then the increment must happen from within the cache while the
     28         // cache global mutex is locked. In this way, we can be rest assured
     29         // that data races can't happen if the cache performs some task if
     30         // the hardRefCount is zero while the global cache mutex is locked.
     31         (void)fromWithinCache;   // Suppress unused variable warning in non-debug builds.
     32         U_ASSERT(fromWithinCache);
     33         cachePtr->incrementItemsInUse();
     34     }
     35 }
     36 
     37 void
     38 SharedObject::removeRef(UBool fromWithinCache) const {
     39     UBool decrementItemsInUse = (umtx_atomic_dec(&hardRefCount) == 0);
     40     UBool allReferencesGone = (umtx_atomic_dec(&totalRefCount) == 0);
     41 
     42     // Although items in use may not be correct immediately, it
     43     // will be correct eventually.
     44     if (decrementItemsInUse && cachePtr != NULL) {
     45         if (fromWithinCache) {
     46             cachePtr->decrementItemsInUse();
     47         } else {
     48             cachePtr->decrementItemsInUseWithLockingAndEviction();
     49         }
     50     }
     51     if (allReferencesGone) {
     52         delete this;
     53     }
     54 }
     55 
     56 void
     57 SharedObject::addSoftRef() const {
     58     umtx_atomic_inc(&totalRefCount);
     59     ++softRefCount;
     60 }
     61 
     62 void
     63 SharedObject::removeSoftRef() const {
     64     --softRefCount;
     65     if (umtx_atomic_dec(&totalRefCount) == 0) {
     66         delete this;
     67     }
     68 }
     69 
     70 int32_t
     71 SharedObject::getRefCount() const {
     72     return umtx_loadAcquire(totalRefCount);
     73 }
     74 
     75 int32_t
     76 SharedObject::getHardRefCount() const {
     77     return umtx_loadAcquire(hardRefCount);
     78 }
     79 
     80 void
     81 SharedObject::deleteIfZeroRefCount() const {
     82     if(getRefCount() == 0) {
     83         delete this;
     84     }
     85 }
     86 
     87 U_NAMESPACE_END
     88